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When to Plant Valerian in Manitowoc County, WI

Manitowoc County, Wisconsin Zone 5b May

May in Manitowoc County, Wisconsin — your action list

We've pulled the most time-sensitive tasks for Manitowoc County, Wisconsin this May and put them front and centre. Tackle them in order.

Avg. last frost April 30
Avg. first frost October 12
Soil temp (4") 58°F
Watering Low
Pest pressure Low
Daylight 14.6 hrs
  1. Time to transplant valerian

    Plant tomatoes deep — bury the stem up to the first true leaves to grow extra roots. Everything else goes in at the same depth it grew in the tray.

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Valerian is a tall perennial herb with fragrant white or pink flower clusters, valued for its root which is used as a natural sleep aid. It attracts pollinators and earthworms.

Manitowoc County, Wisconsin is in USDA Zone 5b. The average last spring frost is April 30 and the first fall frost is October 12, giving you a growing season of approximately 165 days.

At an elevation of 661 feet, Manitowoc County receives approximately 39.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 87°F, providing good warmth for Valerian during the growing season.

Manitowoc County, WI (Zone 5b) Moderate season
165 days
Last Spring Frost April 30
165 growing days
First Fall Frost October 12

Manitowoc County Soil Profile

Soil Type

Silt Loam

Soil pH

5.8-7.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: May 2 🍅 Harvest: Sep 5 – Oct 17
Recommended (50%) ✗ May not fit
Transplant: May 7 🍅 Harvest: Sep 10 – Oct 22
Safe Start (90%) ✗ May not fit
Transplant: May 25 🍅 Harvest: Sep 28 – Nov 9

Percentages indicate frost risk at transplant. The 70% safe window means there is a 30% chance of frost after transplant — suitable for cold-hardy crops or gardeners with frost protection. The 90% safe window is best for tender plants.

Soil Compatibility in Manitowoc County

How your county's soil matches Valerian's growing requirements.

Soil pH

Your soil pH (5.8–7.3) overlaps with Valerian's range (5.5–7.0), though not a perfect match.

Soil Texture

The silt loam soil in Manitowoc County is excellent for Valerian — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is excellent (5.1%) — Valerian will thrive.

How to Plant Valerian

0.5"
Planting Depth
8"
Between Plants
12"
Between Rows

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
1.0″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Valerian

Valerian needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Valerian Needs Rainfall You Supplement Action
Jan 1.5" 0" ❄️ Dormant
Feb 1.9" 0" ❄️ Dormant
Mar 2.8" 0" ❄️ Dormant
Apr 4.3" 3.6" 0.7" 💧 Light watering
May 4.3" 4.4" 0" ✅ Rainfall sufficient
Jun 4.3" 4.9" 0" ✅ Rainfall sufficient
Jul 4.3" 4.8" 0" ✅ Rainfall sufficient
Aug 4.3" 4.1" 0.2" 💧 Light watering
Sep 4.3" 3.8" 0.5" 💧 Light watering
Oct 4.3" 3.1" 1.2" 💧 Light watering
Nov 2.4" 0" ❄️ Dormant
Dec 2.4" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Manitowoc County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Valerian Heat Requirements (GDD)

What are Growing Degree Days (GDD)?

Growing Degree Days measure the total warmth your plants receive during the growing season. Think of it as a "heat bank" — every day above 50°F deposits warmth that helps your plants grow.

Each plant needs a certain amount of accumulated heat to mature. If your county provides more GDD than the plant needs, it's a great fit. If it's close, you may want to choose faster-maturing varieties or start seeds indoors to get a head start.

Valerian needs ~2,288 GDD — county provides 2,516 GDD Good fit

Valerian Planting Timeline — Manitowoc County, WI

Valerian Planting Calendar

Activity When Date Range
Transplant Outdoors May 7 May 7 – May 21
Harvest September 10 Sep 10 – Oct 22

Plant 0.5" deep · 8" apart · Rows 12" apart

Month-by-Month Timeline

MonthActivities
January
February
March
April
May Transplant Outdoors
June
July
August
September Harvest
October Harvest
November
December

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1"/week · Natural rainfall sufficient

📅 Days to Maturity

120–180 days

🧪 Soil pH

Needs 5.5–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 5b

📆 Growing Season

165 days in Manitowoc County

Growing Tips for Valerian in Manitowoc County

Direct sow Valerian outdoors after April 30 in Manitowoc County when soil has warmed and frost danger has passed.

Your 165.0-day growing season in Manitowoc County is tight for Valerian (120.0-180.0 days to maturity). Start indoors and choose early-maturing varieties.

General growing tips

Start seeds indoors and transplant after last frost. Harvest roots in fall of the second year. Deadhead flowers unless you want self-seeding. Cats are attracted to valerian root.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Valerian in Manitowoc County, WI?

Manitowoc County is in Zone 5b with an average last frost of April 30. Plan your Valerian planting based on this frost date — see the calendar above for exact timing.

What planting zone is Manitowoc County, WI?

Manitowoc County, Wisconsin is in USDA Hardiness Zone 5b. The average last spring frost is April 30 and first fall frost is October 12.

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Your Manitowoc County Garden Planner — Free

A 24-page printable planner built for Manitowoc County (Zone 5b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

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Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Manitowoc County, WI. Local conditions may vary. Last updated: May 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.